Electrophoresis has been used for a long time to separate charged molecules according to their difference in migration rate under the influence of an electrical field. Traditionally, the molecules are stained in the gel after electrophoresis by more or less selective dye stains or by staining using colloidal metal particles. The molecules to be separated may also be labelled, for example with a radioactive or fluorescent label, for detection after the electrophoresis. Today it is most common to avoid the use of radioactivity in favour of fluorescent labelling, such as labelling with cyanine dyes.
However, the electrophoretic backings used to carry the electrophoretic slab gel are in many cases fluorescent per se which disturbs the detection procedure. Commonly used electrophoretic support films, such as polyethylene terephtalate (PET) function satisfactorily for relatively large amounts of fluorescence labelled biomolecules but disturb and hinder the detection of low amounts of biomolecules after slab gel electrophoresis. Since this limits the application of the technique in, for example, diagnostic assays it is very important to be able to detect very low amounts of biomolecules in for example a biological sample. Another important area is pharmacological research where most of the pharmacologically interesting proteins occur at very low concentrations compared to high abundance proteins, such as albumin.
To avoid disturbances in the detection of fluorescence labelled samples, electrophoretic supports of glass have been used. Glass enables imaging of low amounts of fluorescence labelled samples. However, glass as electrophoretic support is not desirable of space, weight and safety reasons.
Alternatively, gels are scanned without a support which, of course, minimises the fluorescence background. However, this option is not desirable because it is difficult to handle the gel before and after scanning.
It would be desirable to improve the handling of these gels.
It would also be desirable to be able to use pre-swollen ready to use gels, such as pre-cast DALT™ gels or PHAST™ gels, for fluorescence detection in such a way that scanning of low sample amounts is possible.
Furthermore, it would be desirable to scan any gel for presence of fluorescence after electrophoresis and then to store the gel in a hydrated condition for future use, such as future mass spectrometry analysis.